Custom SUP Fin

I’ve recently bought my own Stand Up Paddle (SUP) board, an inflatable version from Flysurfer, which so far is working really well. But this isn’t a product review! My local paddling spots are all very flat, but the fins that came with the board are very surf oriented. This means that when paddling in flat water there is a lot of drag from the 2 outside fins which are angled out from the center line (see the middle photo), and the board doesn’t travel in a straight line – you have to swap hands every few strokes. It’s not a huge deal, but I was curious to see what difference a large single fin would make since most boards I’ve seen use this. Unfortunately Flysurfer don’t sell them, so it was time to get making!

All I did was use my flatbed scanner to capture the original fin shape (the black one in the right photo), trace the top section in Adobe Illustrator since this is the critical detailing to fit with the board, and then add my own shape for the fin based on the shape of some popular fins online. No 3D CAD required. This was laser cut from a piece of clear acrylic, and I used a file and sandpaper to add some shape to the edges. Voila.

Unfortunately I can’t give this particular design 2 thumbs up, it doesn’t perform quite as well as I expected. While it seems a little easier to glide through the water, the fin doesn’t improve the boards ability to hold a straight line – I think it’s a little bit loose in the socket and tilts on an angle in the water. The acrylic might be a little too thin, but it’s a start. I’ll make some tweaks and try again – it’s nice to make something that’s not 3D printed for a change.

If anyone has any experience playing around with different fin configurations or shapes I’d love to hear from you – I’ve read a few interesting articles from SUPguide.com and Neverbored but there’s only so much you can learn by reading, especially when you have to make your own fins because of the limitations of the inflatable board.

It’s certainly crossed my mind @mr3dprint, but because the part is long and flat, and I have access to laser cutters at my university, it’s just a lot faster and more efficient to do this way. My backup option was to just print the design on paper and use it as a template to cut by hand from acrylic using a jigsaw. I guess it’s a matter of choosing the right technology for the job, and in my opinion, 3D printing isn’t the best way to make this part… But of course it could be done!